Polyester masterbatch composition

ABSTRACT

The present invention relates to masterbatches useful for modifying thermoplastic polyesters, in particular to masterbatches comprising dispersed polyol branching agent and/or chain coupling agents, such as for example dianhydrides. The invention also relates to a method for preparing the masterbatches, and to a method for modifying a polyester utilizing the masterbatches. Yet another aspect of the invention is the use of such a masterbatch composition for the modification of polyesters.

The present invention relates to masterbatches useful for modifyingthermoplastic polyesters, in particular to masterbatches comprisingdispersed polyol branching agents and/or chain coupling agents. Theinvention also relates to a method for preparing the masterbatches, andto a method for modifying a polyester utilizing the masterbatches.

Thermoplastic polyesters such as poly(ethylene terephthalate) (PET) andpoly(butylene terephthalate) (PBT) are widely used in the fields ofextrusion, injection molding and stretch blow molding to produceproducts such as fibers, containers and films.

While polyesters may be used in other fields such as film blowing,tentering, thermnoforming and foam extrusion, their use in these fieldsis often limited by the need for a narrow processing window andspezialised processing equipment. Such limitations generally stem fromdeficiencies in the melt rheology of the polyesters. In particular,polyesters typically have low melt viscosity, low melt strength and lowmelt elasticity.

It is known that the melt strength and melt viscosity of polyesters canbe improved through the introduction of a degree of branching in thelinear chain structure of the polymer, and/or by increasing the polymersmolecular weight through chain extension. One approach used to preparebranched or chain extended polyesters has involved melt mixingpolyesters with branching and/or chain coupling agents such aspolyfunctional carboxylic acids, anhydrides or alcohols. During meltmixing, the agents react with the molten polyester to chain extendand/or introduce branching in the linear chain structure of the polymer.

Depending upon the type of branchingichain coupling agent(s) used tomodify the polyester, the overall effect of the melt mixing reaction mayin fact decrease the molecular weight of the polyester. This will oftenbe the case where the only type of agent used is a polyol branchingagent. Under these circumstances, in order to achieve the desiredincrease in melt strength and melt viscosity, a chain coupling agent canbe used in combination with the polyol, or the resulting branchedpolyester can be subjected to a further processing step such as a solidstate condensation process. In contrast, polyanhydride branching/chaincoupling agents can introduce branching, but also generally cause anincrease in the molecular weight of the polymer during melt mixing.Accordingly, polyanhydride branching/chain coupling agents can be usedas a sole branching/chain coupling agent without subjecting the modifiedpolyester to further processing.

Regardless of the type of branching/chain coupling agent used, toeffectively modify the polyester it is important that the degree ofbranching/chain coupling can be controlled during the melt mixingprocess, and that branching/chain coupling occurs uniformly in thepolyester.

Generally melt mixing is performed in an extruder, and thebranching/chain coupling agent can be added to the polyester eitherbefore extrusion, or to the molten polyester during extrusion. The mostsimplistic way in which the agent can be added to the polyester is bydirect addition. However, this mode of addition has been found to leadto gel formation through excessive localized chain coupling, andnon-uniform branching within the modified polyester. This also leads todetrimental discoloration. Furthermore, it is not uncommon to useamounts of less than 0.5 weight percent of the branching/chain couplingagent, relative to the polyester to be modified. At these low levels, itis difficult to provide a uniform distribution of the agent in thepolyester by direct addition.

Many of the aforementioned problems associated with the addition ofbranching/chain coupling agents can be overcome through use of a polymerblend, concentrate, or masterbatch as it is commonly referred to in theart The masterbatch comprises high levels of the branching/chaincoupling agent, but when added to the polyester it in effect acts as adiluted source of the agent. This diluent effect enables thebranching/chain coupling agent to be distributed more evenly throughoutthe polyester and promotes a more uniformly branched/chain extendedpolyester.

In its simplest form, the masterbatch may be a physical blend of acarrier polymer and the branching/chain coupling agent, with both theagent and the carrier polymer often being in a powdered form. To avoidproblems associated with incompatibility, the carrier polymer ispreferably the same as, or of the same general class as, the basepolymer to which the masterbatch is to be melt mixed with. For example,if the base polymer is a polyester, the carrier polymer is preferablyalso a polyester. Although effective, such physical blends do have atendency to separate out into the individual components and again giverise to non-uniform distribution of the branching/chain coupling agent.

A masterbatch can also be readily formed by melt mixing a carrierpolymer with the branching/chain coupling agent. However, when thecarrier polyester this may lead to problems. In particular, given thatthe branching/chain coupling agents react with a polyester during meltmixing, the same or similar carrier polyester will also generally reactwith the agents during preparation of the masterbatch.

As a means of circumventing this problem, U.S. Pat. No. 5,801,206discloses a masterbatch comprising branching agents where the carrierpolymer is an inert polyolefin. Preparation of a masterbatch of thistype by melt processing does therefore not result in the reaction of thebranching agents with the carrier polymer. Although these masterbatchesprovide a means to add the agents to a polyester, the resulting modifiedpolyester will inherently always be contaminated with polyolefin. Thiscontamination may be tolerable, and possibly desired, in some instances,however it can also be detrimental and—depending on the actual additionlevel—might lead to hazy end products. For example, the quality offoamed polyester can be reduced by the presence of polyolefincontamination.

U.S. Pat. No. 5,536,793 discloses a masterbatch comprising branchingagents where the carrier polymer is a polyester such as PET. In thiscase, the reactivity of the branching agent toward the carrier polymerduring melt processing is used advantageously. In particular, byensuring sufficient branching agent is present during melt mixing, theend groups of the polyester chains are in effect capped by the branchingagent, which in turn is believed to prevent further reaction of thebranching agent with the polyester. By using higher amounts of branchingagent than is required to cap all of the polyester chains, a masterbatchcomprising unreacted branching agent can be prepared.

However, masterbatches disclosed in U.S. Pat. No. 5,536,793 are limitedin terms of composition. Sufficient branching agent to cap the endgroups of the polyester carrier must initially be present during meltmixing to prevent crosslinking and gel formation. In practice, thistypically limits the masterbatch composition to comprising no less than5 weight percent of the branching agent. Furthermore, the cappingreaction disclosed is based on the reaction of the polyester end groupswith a polyfunctional anhydride branching agent. A similar reactionusing other agents such as a polyfunctional alcohol branching agent isunlikely to prevent reaction of the polyol with the carrier polyesterduring melt blending. In particular, polyol compounds are known toreadily react with internal ester groups of a PET chain during a meltblending process (transesterification). Under these circumstances, most,if not all, of the polyol branching agent would react with the polyestercarrier to thereby render the material unsuitable for use as amasterbatch. Accordingly, the composition of the masterbatch disclosedin U.S. Pat. No. 5,536,793 is further limited to the use of apolyfunctional anhydride branching agents.

It would therefore be desirable to provide a masterbatch that compriseda polyester as a carrier material and a branching and/or a couplingagent, wherein the composition of the masterbatch was less restricted interms of the amount and type of the branching and/or coupling agentincorporated.

Surprisingly, it has been found that polyesters having a melt processingtemperature of 250° C. or less can be melt mixed with branching and/orchain coupling agents without significant reaction occurring between thebranching and/or chain coupling agent and the polyester. Under thesecircumstances, a polyester can be melt mixed with a wide array ofbranching and/or chain coupling agents at both high and lowconcentrations to prepare masterbatches useful for subsequent meltmixing with other thermoplastic polyesters. Advantageously, agents suchas polyfunctional acid anhydrides and polyols can be combined togetherwithin the masterbatch of the present invention.

One aspect of the present invention is a polyester masterbatchcomposition comprising a branching and/or a chain coupling agentdispersed within a polymeric matrix of polyester, wherein the polyesterhas a melt processing temperature of 250° C. or less.

As used herein, the term “masterbatch” has the common meaning as wouldbe understood by one skilled in the art. With particular reference tothe present invention, a masterbatch is a composition comprising apolyester as a carrier polymer and an agent, such as a branching and/ora chain coupling agent, where the concentration of the agent is higherthan desired in a final product, and which composition is subsequentlylet down in a base polymer to produce the final product having thedesired amount of agent.

As used herein, the term “melting temperature” of a branching or chaincoupling agent is used to denote a temperature at which the agent beginsto melt.

As used herein, the term “melt processing temperature” of a polyester isused to denote the lowest temperature that the polyester can bemaintained at to enable it to be effectively melt processed.

As used herein, the term “branching agent” or “branching compound” isused to denote a polylunctional compound which can react with apolyester to introduce branching therein. It will be appreciated that inorder to introduce branching, the branching agent will necessarily haveat least three functional groups that are capable of reacting with thepolyester.

As used herein, the phrase “a branching and/or a chain coupling agent”is used to mean at least one chain branching agent or chain couplingagent. It embraces both types of agent and multiple agents incombination.

The branching and/or chain coupling agent in accordance with themasterbatch of the present invention is dispersed within a polymericmatrix of polyester. By “dispersed” is meant that the agent is presentas a separate largely unreacted entity within the polymeric matrix, andhas therefore not reacted with the polymeric matrix to become anintegral part thereof.

In one embodiment of the present invention, the agent(s) selected forthe polyester masterbatch is preferably a branching agent, and thebranching agent is preferably a polyol.

In another embodiment of the present invention, the agent(s) selectedfor the polyester masterbatch is preferably a coupling agent, and thecoupling agent is preferably a dianhydride. It will be appreciated bythose skilled in the art that a dianhydride can also function as abranching agent. For convenience, an agent which can function as both abranching and a coupling agent may herein also be referred to as a“branching/coupling agent”.

In a preferred embodiment of the present invention, the agents selectedfor the polyester masterbatch are a branching agent in conjunction witha coupling agent. In this case, the branching agent is preferably apolyol and the coupling agent is preferably a dianhydride.

It is an important feature of the present invention that the branchingand/or chain coupling agent is dispersed in a polymeric matrix ofpolyester. In particular, that the branching and/or chain coupling agentis melt mixed with the polyester to become dispersed within thepolymeric matrix of the polyester. As discussed above, branching and/orchain coupling agents are renowned for reacting with polyesters duringmelt mixing. Under these circumstances, there are limitations as to thetype and amount of branching and/or chain coupling agents that can beused in the preparation of the masterbatches. Surprisingly, it has beenfound that polyesters having a melt processing temperature of 250° C. orless can be melt mixed with particular branching and/or chain couplingagents without significant reaction occurring between the branchingand/or chain coupling agent and the polyester. Without wishing to belimited by theory, combinations of branching and/or chain couplingagents and polyesters that demonstrate low reactivity toward each otherduring melt mixing are believed to be those where the agent has a highermelting temperature than the melt processing temperature of thepolyester, and/or where the agent has a poor solubility in the moltenpolyester.

In particular when the branching agent is a polyol, it is an importantfeature of the present invention that the polyol is melt mixed with thepolyester to become dispersed within the polymeric matrix of thepolyester. As discussed above, polyol compounds are renowned forreacting with polyesters during melt mixing. Under these circumstances,it is not possible to disperse polyol within the polymeric matrix as thepolyol reacts with the polyester to become an integral part thereof.Surprisingly, it has been found that particular combinations ofpolyesters, with melt processing temperatures below 250° C., and polyolbranching agents can be melt mixed without significant reaction betweenthe polyester and the polyol occurring.

As will be appreciated from the discussion directly above, the lack ofreactivity between the branching and/or chain coupling agent and thepolyester is important. However, it is to be understood that this doesnot exclude the possibility of there being at least some reactivity ofthe agent toward the polyester. In particular, provided that there is nosignificant reaction between the agent and the polyester during meltmixing, it will be possible to prepare a useful masterbatch withbranching and/or chain coupling agent dispersed within a polymericmatrix of polyester.

Preferably, no more than about 50 weight percent, more preferably nomore than about 20 weight percent, still more preferably no more thanabout 10 weight percent, most preferably no more than about 5 weightpercent of the polyester reacts with the branching and/or chain couplingagent during preparation of the masterbatch by melt mixing. In aparticularly preferred embodiment of the present invention,substantially none of the polyester reacts with the branching and/orchain coupling agent during preparation of the masterbatch by meltmixing.

By the phrase “the polyester reacts with the branching and/or chaincoupling agent” is meant that polyester chain end groups and/or internalmoieties within the polyester chain react with the branching and/orchain coupling agent.

The degree of reaction that may occur between the branching and/or chaincoupling agent and the polyester during preparation of the masterbatchcan typically be assessed by a number of convenient and simpletechniques. The simplest technique is to measure the melt flow index(MFI) of the masterbatch. Significant reaction of a branching agent suchas pentaerythritol with the polyester will be evidenced by an increasein the polyesters MFI, whereas significant reaction of a branching/chaincoupling agent such as pyromellitic dianhydride (PMDA) will be evidencedby a decrease in the polyesters MFI. The same can be detected bymeasuring the Intrinsic Viscosity of the carrier polyester.

The composition of the masterbatch may also be analyzed using techniquessuch as NMR and IR spectroscopy, where end group determination can beusefully applied. Alternatively, depending upon the choice of branchingand/or chain coupling agent and polyester, the masterbatch could beextracted using an appropriate solvent to selectively isolate unreactedagent. Mass balance calculations could then be used to establish thedegree of reactivity.

Reaction of the branching and/or chain coupling agent with the polyesterwill typically cause chain scission or chain coupling of the polyesterchains, this in turn will be reflected in a reduction or increase,respectively, in the polyesters melt viscosity and/or the polyestersintrinsic viscosity (IV). For example reaction of the polyol with thepolyester will typically cause chain scission of the polyester chains,this in turn will be reflected in a reduction of the polyesters meltviscosity and/or the polyesters intrinsic viscosity (IV).

The viscosity of the polyester melt during melt mixing can be readilyassessed by measuring the force required to drive the mixing elements ofthe melt mixing device. In the case where the viscosity of the melt isreduced, the force required to drive the mixing elements will alsogenerally be reduced, and where the viscosity of the melt is increased,the force required will also generally be increased. Where an extruderis used, this force can conveniently be determined by measuring themotor drive torque of the extruder. A reduction or increase in the IV ofthe polyester can be conveniently measured using techniques well knownin the art.

A particular advantage provided by the masterbatch of the presentinvention is that it can be prepared using a diverse range of branchingand/or chain coupling agents at both high and low concentrations withoutsignificant change in the rheological properties of the carrierpolyester occurring. This advantage is particularly evident where apolyol branching agent is employed, or where low levels (from about 1 toabout 5 weight percent) of a branching/chain coupling agent such aspyromelletic dianhydride are employed.

It will be appreciated by those skilled in the art the addition of someadditives to a molten polymer may cause the melt viscosity of thepolymer/additive mixture to increase or decrease simply through anadditive being present in the melt, and not through any reaction of theadditives with the polymer. Accordingly, such an increase or decrease inmelt viscosity of the polymer/additive mixture should not be consideredas an increase or decrease in the polymers melt viscosity per se.

Preferably, the polyesters melt viscosity and/or the polyestersintrinsic viscosity is reduced or increased by no more than 30%, morepreferably no more than 15%, more preferably no more than 5% when it ismelt mixed with the branching and/or chain coupling agent. In aparticularly preferred embodiment, the melt viscosity and/or theintrinsic viscosity of the polyester remains substantially unchangedwhen it is melt mixed with the branching and/or chain coupling agent.

By virtue of there being no significant reaction between the branchingand/or chain coupling agent and the polyester during melt mixing, theresulting masterbatch can be readily extruded and generally will haveadequate physical and mechanical properties to function as amasterbatch. In particular, the molecular weight of the polyester is notreduced or increased during preparation of the masterbatch to a pointwhere extrusion becomes impractical and/or difficult.

As discussed above, the relative melt temperatures of the branchingand/or chain coupling agent and the polyester, and/or the solubility ofthe agent in the molten polyester are believed to be importantparameters that influence the reactivity of the agent toward thepolyester. Depending upon the particular combination of agent andpolyester, any one of these parameters may influence the reactivity, oraltemauvely both parameters may collectively influence the reactivity.

Preferably, the branching and/or chain coupling agent has a melttemperature which is at least 10° C. higher, more preferably at least20° C. higher, still more preferably at least 40° C. higher than themelt processing temperature of the polyester.

Preferably, branching and/or chain coupling agent is present as aseparate phase in the molten polyester during melt mixing. Inparticular, it is preferred that at least 50 weight percent, morepreferably at least 65 weight percent, most preferably at least 85weight percent of the branching and/or chain coupling agent is presentas a separate phase in the molten polyester during melt mixing. In aparticularly preferred embodiment, substantially all of the branchingand/or chain coupling agent is present as a separate phase in the moltenpolyester during melt mixing.

In the immediately preceding paragraph, reference to the “moltenpolyester during melt mixing” is intended to be a reference to themolten polyester at the melt processing temperature of that polyester.

The masterbatch of the present invention provides a means ofdistributing the branching and/or chain coupling agent uniformly in abase polyester. In order to ensure branching and/or chain extensionoccurs uniformly in the base polyester during melt mixing, it isimportant that the masterbatch rapidly melts to thereby rapidly dispersethe agent throughout the molten base polyester. It is believed that theagent can be more efficiently dispersed throughout the base polyesterwhen the melt processing temperature of the masterbatch carrierpolyester is lower than that of the base polyester.

A common base polyester that may be modified using a masterbatch inaccordance with the present invention is PET. Suitable polyesters foruse as the carrier polyester in the masterbatch of the present inventionhave a melt processing temperature of 250° C. or less, which isadvantageously lower than that of PET (typically about 260° C.).Utilizing such low melt processing temperature polyesters also providesa means of increasing the melt temperature difference between thecarrier polyester and branching and/or chain coupling agents having melttemperatures greater or around 250° C., the effect of which is believedto reduce reactivity of the agent toward the carrier polyester duringpreparation of the masterbatch.

Preferably, a low melt processing temperature polyester suitable for usein the masterbatch will have a melt processing temperature ranging from150° C. to 250° C., more preferably from about 170° C. to about 240° C.,most preferably from about 180° C. to about 230° C.

In considering suitable low melt processing polyesters for use inaccordance with the present invention, those skilled in the art willappreciate that there are numerous factors which influence the meltingproperties of polyesters. Factors that are believed to contribute toproviding a low melting polyester include chain structure irregularity,non-linear connection of monomeric units, lack of interchain attraction,bulky side chains, flexibility in the internal bond structure and an oddnumber of carbon atoms in the repeat units. Many of these factors ineffect inhibit the ability of the polyester to develop crystallinity,and therefore polyesters having a low percentage of crystallinity oftenalso have a low melt processing temperature.

The degree of crystallinity can, for example, be measured by varioustechniques, known by those skilled in the art. For instance differentialscanning calorimetry (DSC) detects the heat of fusion at the melttemperature, which is directly proportional to the degree ofcrystallinity. The density of the polyester is also linked to the degreeof crystallinity: as lower the density as higher is the degree ofcrystallinity. Both methods need calibration tests. An absolute methodof detecting the degree of crystallinity is, for example, wide angleX-ray scattering. Where a low crystalline polyester is used as a lowmelt processing temperature polyester, it preferably has a crystallinityof less than about 15%, more preferably of less than about 5%.

It is particularly preferred that such a low crystalline polyester hassubstantially no crystallinity and is amorphous.

Another important parameter of low melt processing polyesters is theirglass transition temperature: Suitable polyesters show a glasstransition temperature of about 70° C., more preferably about 110° C.and most preferably about 150° C. below the melting temperature of thebranching agent or chain coupling agent.

Those skilled in the art will appreciate that the degree ofcrystallinity of a given polyester will very much depend upon themolecular structure of the polyester. In particular, the degree ofcrystallinity of a polyester can be altered by simply changing theamount and/or type and/or distribution of monomer units that make up thepolyester chain. For example, if about 8 mole percent of the ethyleneglycol repeat units in PET are replaced with 1,4-cydohexanedimethanolrepeat units, or about 15 mole percent by di-ethylene glycol repeatunits, the resulting modified polyester can be amorphous and has a lowmelt processing temperature. Similarly, if about 15 mole percent of theterephthalic acid repeat units in PET are replaced with isophthalic acidrepeat units, the resulting modified polyester can also be amorphous andhave a low melt processing temperature. Such concepts can also becombined into one polyester or by melt mixing at least 2 differentpolyesters. Accordingly, the choice of a particular modifying acid ordiol can significantly affect the melt processing properties of thepolyester.

As used herein, the terms “modifying acid” and “modifying diol” aremeant to define compounds, which can form part of the acid and diolrepeat units of a polyester, respectively, and which can modify apolyester to reduce its crystallinity or render the polyester amorphous.

Examples of modifying add components may include, but are not limitedto, isophthalic acid, phthalic acid, 1,3-cyclohexanedicarboxylic acid,succinic acid, glutaric acid, adipic acid, sebacic acid, suberic acid,1,12-dodecanedioic acid, and the like. In practice, it is oftenpreferable to use a functional acid derivative thereof such as thedimethyl, diethyl, or dipropyl ester of the dicarboxylic acid. Theanhydrides or acid halides of these acids also may be employed wherepractical. Preferred is isophthalic acid.

Examples of modifying diol components may include, but are not limitedto, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propanediol,1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-cyclohexanediol,1,4-cyclohexanediol, 1,2-cyclohexanedimethanol,1,3-cyclohexanedimethanol,Z,8-bis(hydroxymethyltricyclo-[5.2.1.0]-decane wherein Z represents 3,4, or 5; 1,4-Bis(2-hydroxyethoxy)benzene and diols containing one ormore oxygen atoms in the chain, e.g. diethylene glycol, triethyleneglycol, dipropylene glycol, tripropylene glycol, and the like. Ingeneral, these diols contain 2 to 18, preferably 2 to 8 carbon atoms.Cycloalphatic diols can be employed in their cis or trans configurationor as mixtures of both forms. 1,4-cyclohexanedimethanol or di-ethyleneglycol are the preferred modifying diols.

Other suitable low melt processing polyesters are based on polyadditionof lactones, for example poly-ε-caprolacton.

Preferred is a polyester masterbatch composition wherein the polyestersuitable for use in the masterbatch is glycol modified poly(ethyleneterephthalate) (PET-G), poly-ε-caprolactone, or a copolyester containinggreater than about 15% isophthalic units.

Polyesters suitable for use in the masterbatch of the present inventiongenerally have an intrinsic viscosity (IV) of about 0.4 dL/g to about1.5 dL/g, but those having values of about 0.6 dL/g to about 1.0 dL/gare preferred. Intrinsic viscosity can be determined in a 60/40 (wt/wt)phenol/tetrachloroethane solution at a concentration of 0.5 grams per100 ml at 25° C.

In a specific embodiment the polyester for use in the masterbatch, ischaracterized by a melt viscosity of less than 2000 Pa sec at a shearrate of 100 s⁻¹ measured at a temperature below the meltingtemperature(s) of the branching agent and/or chain coupling agent

Below the melting temperature of the branching agent and/or chaincoupling agent means at least 10° C. and preferably at least 20° C.below said temperature.

The masterbatch in accordance with the present invention may comprise abranching agent. Preferred branching agents include, but are not limitedto, polyols and polyfunctional acid an hydrides.

Suitable polyol branching agents for use in the masterbatch have afunctionality of three or more, which will be understood to mean thatthey have at least three hydroxy groups per molecule. For example,glycerol has a functionality of three and pentaerythritol has afunctionality of four. Examples of suitable polyol branching agents, orprecursors thereto, indude, but are not limited to, trimethylolethane,pentaerythritol sorbitol, 1,1,4,4-tetrakis(hydroxymethyl)cyclohexane,and dipentaerythritol, tripentaerythritol etc. One or more polyolbranching agent may be used in combination.

Preferred polyol branching agents, or derivatives thereof, includepentaerythritol, dipentaerythritol, tripentaerythritol, andtrimethylolethane.

As indicated above, the polyol branching agent may be provided in theform of a precursor thereto, or derivative thereof. By “precursorthereto” or “derivative thereof” it is meant a compound that isconverted to the polyol during preparation of the masterbatch by meltprocessing.

Where the masterbatch in accordance with the present invention comprisesa polyol branching agent, the polyol is preferably present in an amountfrom about 0.3 to about 30 weight percent, more preferably from about0.3 to about 20 weight percent, most preferably from about 1 to about 10weight percent, relative to the polyester carrier polymer.

Suitable polyfunctional acid anhydrides fbr use in the masterbatch havea functionality of three or more, which will be understood to mean thatthe polyfunctional acid anhydrides have at least three acid groups oracid group residues per molecule. For example, trimellitic acidanhydride has a functionality of three and pyromellitic acid dianhydridehas a functionality of four.

Examples of polyfunctional and anhydrides that can be used in themasterbatch of the present invention include aromatic acid anhydrides,cyclic aliphatic anhydrides, halogenated acid anhydrides, pyromelliticdianhydride, benzophenonetetracarboxylic acid dianhydride,cyclopentanetetracarboxylic dianhydride, diphenyl sulfonetetracarboxylic dianhydride,5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylicdianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride,bis(3,4-dicarboxyphenyl)thioether dianhydride, bisphenol-A bisetherdianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride,2,3,6,7-napthalenetetracarboxylic acid dianhydride,bis(3,4-dicarboxyphenyl)sulfone dianhydride,1,2,5,6-napthalenetetracarboxylic acid dianhydride,2,2′,3,3′-biphenyltetracarboxylic acid, hydroquinone bisetherdianhydride, 3,4,9,10-perylene tetracarboxylic acid dianhydride,1,2,3,4-cyclobutanetetracarboxylic acid dianhydride,3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene-succinic aciddianhydride, bicyclo(2,2)oct-7-ene-2,3,5,6-tetracarboxylic aciddianhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic acid dianhydride,2,2-bis(3,4-dicarboxyphenyl)propane dianhydride,3,3′,4,4′-biphenyltetracarboxylic acid dianhydride, 4,4′-oxydiphthalicdianhydride (ODPA), and ethylenediamine tetraacetic acid dianhydride(EDTAh). It is also possible to use acid anhydride containing polymersor copolymers as the anhydride component. Two or more polyfunctionalacid anhydrides may be used in combination.

Preferred polyfunctional acid anhydrides, indude pyromelliticdianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride,1,2,3,4-cyclobutanetetracarboxylic acid dianhydride andtetrahydrofuran-2,3,4,5-tetracarboxylic acid dianhydride. Mostpreferably the polyfunctional acid anhydride is pyromelliticdianhydride.

As indicated above, the polyfunctional acid anhydride may contain acidgroups or acid group residues. By “acid group residue” is meant aresidue of a carboxylic acid that has condensed with a second carboxylicacid to form an anhydride. In this case, the anhydride formed wouldcontain two acid group residues.

Where the masterbatch in accordance with the present invention comprisesa branching agent other than a polyol branching agent, the branchingagent is preferably present in an amount from about 1 to about 60 weightpercent, more preferably from about 5 to about 40 weight percent, mostpreferably from about 5 to about 30 weight percent, relative to thepolyester carrier polymer.

The masterbatch in accordance with the present invention may comprise achain coupling agent. Chain coupling agents that may be used with thepresent invention indude, but are not limited to, polyfunctional acidanhydrides, epoxy compounds, oxazoline derivatives, oxazolinonederivatives, lactams and related species. For examples of additionalchain coupling agents we refer to Inata and Matsumura, J. App. Pol.Sci., 303325 (1988) and Lootqens et al J. App. Pol. Sci 65 1813 (1997)and Brown in “Reactive Extrusion” Ed Xanthos, Hanger, N.Y. 1992 p 75.

Those containing anhydride or lactam units are preferred for reactionwith alcohol functionality of a base polyester when the masterbatch issubsequently used. Those containing oxazoline, oxazolinone, epoxide,carbodiimide units are preferred for reaction with acid functionality ofa base polyester when the masterbatch is subsequently used.

Preferred chain coupling agents which may be used alone or incombination include the following:

(1) Polyepoxides such as bisphenole-A-diglycidylether,ebis(3,4-epoxycycohexylmethyl) adipate; N,N-diglycidyl bemzamide (andrelated diepoxies); N,N-diglycidyl aniline and derivatives;N,N-diglycidylhydantoin, uracil, barbituric acid or isocyanuric acidderivatives; N,N-diglycidyl diimides; N,N-diglycidyl imidazolones; epoxynovolaks; phenyl glycidyl ether; diethyleneglycol diglycidyl ether;Epikote 815 (diglycidyl ether of bisphenol A-epichlorohydrin oligomer).

(2) Polyoxazolines/Polyoxazolones such as 2,2-bis(2-oxazoline);1,3-phenylene bis (2-oxazoline-2), 1,2-bis(2-oxazolinyl-2)ethane;2-phenyl-1,3-oxazoline; 2,2′-bis(5,6-dihydro-4H-1,3-oxazoline);N,N′-hexamethylenebis (carbamoyl-2-oxazoline; bis[5(4H)-oxazolone);bis(4H-3,1 benzoxazin-4-one); 2,2′-bis(H-3,1-benzozin-4-one);

(3) Polyisocyanates such as 4,4′-methylenebis(phenyl isocyanate) (MDI);toluene diisocyanate, isocyanate terminated polyurethanes; isocyanateterminated polymers;

(4) Anhydrides

Examples of polyfunctional acid anhydrides are as previously defined forthe branching agents.

(5) Polyacyllactams such as N,N′-terephthaloylbis(carpolactam) andN,N′-terephthaloylbis-(laurolactam). The use of these and similarcompounds for PET chain extension has been disclosed by Akkapeddi andGervasi in U.S. Pat. No. 4,857,603.

(6) Phosphorous (III) coupling agents such as triphenyl phosphite(Jaques et al Polymer 38 5367 (1997)) and other compounds such as thosedisclosed by Aharoni in U.S. Pat. No. 5,326,830. Where the masterbatchin accordance with the present invention comprises a chain couplingagent, the chain coupling agent is preferably present in an amount offrom about 1 to about 60 weight percent, more preferably from about 5 toabout 40 weight percent, more preferably from about 5 to about 30 weightpercent, relative to the polyester carrier.

In a further embodiment of the invention the masterbatch composition maycomprise additionally a phosphite, a phospinate or a phosphonatecompound.

Phosphonates are in general preferred.

Preferably the phosphonate is of formula II

wherein

R₁₀₃ is H, C₁-C₂₀alkyl, unsubstituted or C₁-C₄alkyl-substituted phenylor naphthyl,

R₁₀₄ is hydrogen, C₁-C₂₀alkyl, unsubstituted or C₁-C₄alkyl-substitutedphenyl or naphthyl; or

M^(r+)/r,

M^(r+) is an r-valent metal cation or the ammonium ion,

n is 0, 1, 2, 3, 4, 5 or 6, and

r is 1, 2, 3 or 4;

Q is hydrogen, —X—C(O)—OR₁₀₇, or a radical

R₁₀₁ is isopropyl, tert-butyl, cydohexyl, or cyclohexyl which issubstituted by 1-3 C₁-C₄alkyl groups,

R₁₀₂ is hydrogen, C₁-C₄alkyl, cyclohexyl, or cyclohexyl which issubstituted by 1-3 C₁-C₄alkyl groups,

R₁₀₅ is H, C₁-C₁₈alkyl, OH, halogen or C₃-C₇cycloalkyl;

R₁₀₆ is H, methyl, trimethylsilyl, benzyl, phenyl, sulfonyl orC₁-C₁₈alkyl;

R₁₀₇ is H, C₁-C₁₀alkyl or C₃-C₇cycloalkyl; and

X is phenylene, C₁-C₄alkyl group-substituted phenylene or cyclohexylene.

Other suitable phosphonates are listed below.

Sterically hindered hydmxyphenylalkylphosphonic acid esters orhalf-esters, such as those known from U.S. Pat. No. 4,778,840, arepreferred.

Halogen is fluoro, chloro, bromo or iodo.

Alkyl substituents containing up to 18 carbon atoms are suitablyradicals such as methyl, ethyl, propyl, butyl, pentyl, hexyl and octyl,stearyl and also corresponding branched isomers; C₂-C₄alkyl and isooctylare preferred.

C₁-C₄Alkyl-substituted phenyl or naphthyl which preferably contain 1 to3, more preferably 1 or 2, alkyl groups is e.g. o-, m- orp-methylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl,2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl,3,5-dimethylphenyl, 2-methyl-6-ethylphenyl, 4-tert-butylphenyl,2-ethylphenyl, 2,6-diethylphenyl, 1-methylnaphthyl, 2-methylnaphthyl,4-methylnaphthyl, 1,6-dimethylnaphthyl or 4-tert-butylnaphthyl.

C₁-C₄Alkyl-substituted cyclohexyl which preferably contains 1 to 3, morepreferably 1 or 2, branched or unbranched alkyl group radicals, is e.g.cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl,methylcyclohexyl, dimethylcyclohexyl, trimethylcyclohexyl ortert-butylcyclohexyl.

A mono-, di-, tri- or tetra-valent metal cation is preferably an alkalimetal, alkaline earth metal, heavy metal or aluminium cation, forexample Na⁺, K⁺, Mg⁺⁺, Ca⁺⁺, Ba⁺⁺, Zn⁺⁺, Al⁺⁺⁺, or Ti⁺⁺⁺⁺, Ca⁺⁺ isparticularly preferred.

Preferred compounds of formula I are those containing at least onetert-butyl group as R₁ or R₂. Very particularly preferred compounds arethose, wherein R₁ and R₂ are at the same time tert-butyl.

n is preferably 1 or 2 and, in particular 1.

For example the phosphonate is of formula IIa

wherein

R₁₀₁ is H, isopropyl, tert-butyl, cyclohexyl, or cyclohexyl which issubstituted by 1-3 C₁-C₄alkyl groups,

R₁₀₂ is hydrogen, C₁-C₄alkyl, cydohexyl, or cyclohexyl which issubstituted by 1-3 C₁ -C₄alkyl groups,

R₁₀₃ is C₁-C₂₀alkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl ornaphthyl,

R₁₀₄ is hydrogen, C₁-C₂oalkyl, unsubstituted or C₁-C₄alkyl-substitutedphenyl or naphthyl; or

M^(r+)/r;

M^(r+) is an r-valent metal cation, r is 1, 2, 3 or 4; and

n is 1, 2, 3, 4, 5 or 6.

Preferably the phosphonate is of formula III, IV, V, VI or VII

wherein the R₁₀₁ are each independently of one another hydrogen orM^(r+)/r.

Some of the compounds of formulas II, IIa, III, IV, V, VI, VII and VIIIare commercially available or can be prepared by standard processes, asfor example described in U.S. Pat. No. 4,778,840.

The phosphinates are of the formula XX

-   -   wherein    -   R₂₀₁ is hydrogen, C₁-C₂₀alkyl, phenyl or C₁-C₄alkyl substituted        phenyl; biphenyl, naphthyl, —CH₂O-C₁-C₂₀alkyl or        —CH₂—S-C₁-C₂₀alkyl,    -   R₂₀₂ is C₁-C₂₀alkyl, phenyl or C₁-C₄alkyl substituted phenyl;        biphenyl, naphthyl, —CH₂—O-C₁-C₂₀alkyl or —CH₂S-C₁-C₂₀alkyl, or        R₁ and R₂ together are a radical of the formula XXI    -   wherein    -   R₂₀₃, R₂₀₄ and R₂₀₅ independently of each other are C₁-C₂₀alkyl,        phenyl or C₁-C₄alkyl substituted phenyl.

A specific phosphinate is for example compound 101

Typical phosphites useful in the instant invention are for examplelisted below.

For example triphenyl phosphite, diphenyl alkyl phosphites, phenyldialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite,trioctadecyl phosphite, distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl) phosphde, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,diisodecyloxypentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butyl-phenyl)pentaerythritol diphosphite, tristearylsorbitol triphosphite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin,2,2′,2″-nitriloftriethyltris(3,3′,5,5′-etra-ert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite,5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane.

Especially preferred are the following phosphites:

Tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168, Ciba SpecialtyChemicals), tris(nonyl-phenyl) phosphite,

The masterbatch of the present invention is prepared by melt mixing apolyester with a branching and/or chain coupling agent. Melt mixing canbe performed using methods well known in the art. Preferably, meltmixing is achieved by continuous extrusion equipment such as twin screwextruders, single screw extruders, other multiple screw extruders, suchas Buss kneaders and Farell mixers. Preferably, melt mixing is performedso as to maintain the polyester at its melt processing temperature.

In preparing the masterbatch, one or more polyesters and one or morebranching and/or chain coupling agents may be used.

Consequently in another aspect, the present invention provides a methodof preparing a polyester masterbatch comprising melt mixing a polyesterwith a branching and/or chain coupling agent such that the branchingand/or chain coupling agent is dispersed within the polymeric matrix ofthe polyester, wherein the polyester has a melt processing temperatureof 250° C. or less.

A specific embodiment of the invention is a process for melt processinga base polyester comprising:

-   -   (1) formation of a molten mixture comprising        -   (i) a major amount of a first resin composition comprising            base polyester and from 0 up to about 1 weight % of the            chain coupling agent and/or branching agent, and        -   (ii) a minor amount of the above described polyester master            batch composition comprising at least about 50 weight %            polyester resin and greater than about 2 weight % of a chain            coupling agent and/or branching agent,        -   wherein the relative amounts of (i) and (ii) are such that            said molten mixture comprises from about 0.1 wt % to about 1            wt % of said chain coupling agent and/or branching agent;    -   (2) melt processing of the resultant molten mixture under        conditions of time and temperature sufficient to modify the base        polyester; and    -   (3) direct fabrication of the molten mixture into a film, sheet,        injection molded article, fiber or non-woven.

Suitable melt processing conditions are described above.

The term “direct fabrication” as used herein should be understood tomean that the molten mixture of base polymer and masterbatch is notfirst converted to powder or pellets for subsequent remelting in a laterfabrication of desired articles, but is instead immediately meltfabricated into such article.

The definitions and preferences given above for the composition alsoapply for the process of manufacturing a polyester master batch.

The process of preparing the masterbatch can be performed in one or moreprocessing steps.

Moreover, all the ingredients of the masterbatch can be mixed before andmetered into an extruder, or metered separately.

Another option is the extrusion of one part of the masterbatch, andadding the other parts of the masterbatch later in the process. Forexample, the carrier polyester is metered into the extruder right fromthe beginning, and the active ingredients are metered in higherextrusion zones.

The masterbatch can be supplemented to a solid-state polycondensationfor increasing the molecular weight of the carrier polyester. This isuseful for adjusting the molecular weight of the polyester within themasterbatch to the molecular weight of the base polyester to bemodified.

The masterbatches of the present invention may be used to modify a basepolyester by melt mixing the base polyester with the masterbatch. Asingle masterbatch or a combination of masterbatches may be used. Bythis method, the polyester is modified through reaction with thebranching agent to introduce branching within, or chain extend, thepolyester chain structure. Typically, the base polyester will have ahigher melt processing temperature than the masterbatch carrierpolyester. Accordingly, at these higher temperatures the branchingand/or chain coupling agent will have a greater tendency to react withthe base polyester to chain extend it, and/or introduce branchingpoints.

If desired, the modified polyester can be subjected to furtherprocessing, such as a solid state condensation process, to increase itsmolecular weight. Altematively, where a chain coupling agent has notbeen used, the modified polyester may be subsequently melt mixed with achain coupling agent to increase its molecular weight. Preferably, thebase polyester is melt mixed with a masterbatch comprising a chaincoupling agent.

High melt strength polyesters may be obtained by melt mixing a basepolyester with a polyol branching agent and a polyfunctional acidanhydride. In one preferred embodiment of the present invention a basepolyester is modified using a combination of masterbatches prepared inaccordance with the present invention comprising a polyol branchingagent and a polyfunctional acid anhydride, respectively.

In another preferred embodiment of the invention, the masterbatchcomprises a combination of a polyol branching agent and a polyfunctionalacid anhydride. By combining these two agents in the masterbatch, theneed for two separate masterbatches is conveniently avoided. It isbelieved that by selecting the carrier polyester, the polyol and theanhydride in accordance with the present invention, the masterbatch maybe prepared without significant reaction between the carrier polyester,the polyol and the anhydride occurring. Accordingly, such a masterbatchadvantageously comprises both a polyol branching agent and apolyfunctional acid anhydride dispersed within a polymeric matrix ofpolyester.

Other chain coupling agents may also be combined with a polyol branchingagent in a masterbatch according to the present invention.

Where a masterbatch comprising a combination of branching and/or chaincoupling agents is prepared, it may be that the branching and/or chaincoupling agents react with each other to some extent during melt mixing.In this case, the resulting reaction product(s) may also be a branchingand/or chain coupling agent(s) in its own right and therefore be asuitable agent(s) to act as a branching and/or chain coupling agent inaccordance with the present invention.

In a further aspect, the present invention provides a method formodifying a polyester comprising melt mixing the polyester at atemperature above 250° C. together with a polyester masterbatch asdescribed above.

Polyesters that can be modified by the method of the present inventionare preferably thermoplastic polyesters and include all heterochainmacromolecular compounds that possess repeat carboxylate ester groups inthe backbone of the polymer. Also suitable for use as polyesters arepolymers which contain esters on side chains or grafts, copolymers whichincorporate monomers having carboxylate ester groups (in the backbone oras side groups or grafts) and derivatives of polyesters which retain thecarboxylate ester groups (in the backbone or side groups or grafts). Thepolyesters may also contain acids, anhydrides and alcohols in thebackbone or as side chains (eg acrylic and methacrylic containingpolymers). Preferred polyesters include poly(ethylene terephthalate)(PET), poly(butylene terephthalate) (PBT), poly(ethylene naphthalate)(PEN), poly(tri-methylene terephthalate) (PTT), copolymers of PET,copolymers of PBT, copolymers of PEN, liquid crystalline polyesters(LCP) and polyesters of carbonic acid (polycarbonates) and blends of oneor more thereof.

Copolymers of PET indude variants containing other comonomers. Forexample, the ethane diol may be replaced with other diols such ascyclohexane dimethanol to form a PET copolymer. Copolymers of PBTinclude variants containing other comonomers. Copolymers of PEN includevariants containing other comonomers. Copolymers of PEN/PET are alsouseful in the present invention. These copolymers may be blended withother polyesters.

Liquid crystalline polyesters include poly(hydroxybenzoic acid) (HBA),poly(2-hydroxy-6-naphthoic acid) and poly(naphthalene terephthalate)(PNT) which is a copolymer of 2,6-dihydroxynaphthalene and terephthalicacid. Copolymers of liquid crystal polyesters with other polyesters arealso suitable.

Side chain or graft ester, acid or alcohol containing polymers include:poly(methyl methacrylate) (or other methacrylates or acrylates);poly(methacrylic acid); poly(acrylic acid); poly(hydroxyethylmethacrylate), starch, cellulose etc.

Copolymers or graft copolymers containing acid, ester or alcohol groupsindude ethylene co-vinyl acetate, ethylene co-vinyl alcohol, ethyleneco-acrylic acid, maleic anhydride grafted polyethylene, polypropyleneetc.

Where the masterbatch of the present invention comprises a polyolbranching agent and a polyfunctional acid anhydride, it is preferredthat the molar ratio of the polyfunctional acid anhydride to the polyolbranching agent, or precursor thereto, is in the range of 0.5:1 to(10×C):1, where C is the number of moles of hydroxy groups per mole ofpolyol branching agent. It is particularly preferred that the molarratio of polyfunctional acid anhydride to polyol, or precursor thereto,is in the range of from 2:1 to (2×C):1.

In order to clearly demonstrate the calculation of the molar ratio thefollowing example is provided:

Example Calculation: Masterbatch composition comprising pyromelliticdianhydride (PMDA) and pentaerythritol.

PMDA=tetra functional anhydride

Pentaerythritol=tetra functional alcohol

The polyol, pentaerythritol, used in this example has a functionality of4, therefore C=4.

The mole ratio of PMDA to pentaerythritol is therefore in the range offrom 0.2:1 to 40 (10×4):1, with the preferred mole ratio of PMDA topentaerythritol being in the range of from 2:1 to 8 (2×4):1.Accordingly, a masterbatch comprising 2.5 weight percent ofpentaerythritol would comprise PMDA preferably in an amount ranging fromabout 8 weight percent to about 32 weight percent (ie in a mole ratioranging from 2:1 to 8:1).

Where the masterbatch of the present invention only comprises one of apolyfunctional acid anhydride or a polyol branching agent, but themasterbatch is used to modify a base polyester where both a polyol andan anhydride are used, the molar ratio of polyol branching agent andpolyfunctional acid anhydride is also preferably as previously defined.

The masterbatch in accordance with the present invention may compriseother additives such as fillers, pigments, stabilizers, blowing agents,nucleating agents etc. For examples of these and other suitableadditional additives see U.S. Pat. No. 6,469,078.

The masterbatch may also comprise additives, such as heat stabilizers,light stabilizers, processing stabilizers, metal deactivators,nucleating agents and optical brighteners. Examples are given below.

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexyl phenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which are linearor branched in the side chains, for example 2,6-di-nonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-1′-methyltridec-1′-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-dodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octade-cyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis(3,5-di-tert-butyl-4-hyroxyphenyl) adipate.

1.4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol,δ-tocopherol and mixtures thereof (vitamin E).

1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis(3,6-di-sec-amylphenol),4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)-disulfide.

1.6. Alkylidenebisphenols, for example2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)-phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O-, N- and S-benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether,octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate,tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxy-benzyl)sulfide,isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates, for exampledioctadecyl-2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)malonate,di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate,didodecylmercaptoethyl-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,bis([4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Aromatic hydroxybenzyl compounds, for example1,3,5-tris(3,5-di-tert-butyl4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butylhydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butylhydroxybenzyl)phenol.

1.10. Triazine compounds, for example2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenoxy-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenylethyl-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionylyhexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicydohexyl-4-hydroxybenzyl)isocyanurate.

1.11. Benzylphosphonates, for exampledimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate,diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, thecalcium salt of the monoethyl ester of3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

1.12. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3.5-di-tert-butyl-4-hydroxyphenyly)-propionic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol,n-octanol, 1-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol,n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis-(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane;3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]-undecane.

1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono-or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g.N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamide,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamide,N,N′-bis(3,5di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide,N,N′-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide(Naugard® XL-1, supplied by Uniroyal).

1.18. Ascorbic acid (vitamin C)

1.19. Aminic antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyly)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenyl-amine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylamino-methylphenol,2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1,3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butylutert-octyldiphenylamines, a mixture of mono- anddialkylated nonyidiphenylamines, a mixture of mono- and dialkylateddodecyidiphenylamines, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamines, a mixture of mono- and dialkylatedtert-butyidiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyltert-octylphenothiazines, a mixture of mono- and dialkylatedtert-octylphenothiazines, N-allylphenothiazine,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethylpiperid-4-yl-hexamethylenediamine,bis(2,2,6,6-tetramethylpiperid-4-yl)sebacate,2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

2. UV absorbers and light stabilisers

2.1. 2-(2′-Hydroxyphenyl)benzotriazoles, for example2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-3′-tert-butyl-2′-hydroxy-5′-methylphenyl-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyl-oxy)carbonylethyl]-2′-hydroxyphenyl-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[242-othylhexyloxy)carbonylethyl]-2′-hydroxy-phenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutylbenzotriazole-2-ylphenol];the transesterification product of2-[3-tert-butyl-5′-(2-methoxycarbonylethyl-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol 300; [R—CH₂CH₂—COO—CH₂CH₂—]₂, whereR=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl,2-[2′-hydroxy-3′-(α,α-dimethylbenzyl)-5′-(1,1,3,3-tetramethylbutyl)phenyl]-benzotriazole;2-[2′-hydroxy-3′-(1,1,3,3-tetramethylbutyl)5′-(α,α-dimethylbenzyl)phenyl]benzotriazole.

2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxyand 2′-hydroxy-4,4′-dimethoxy derivatives.

2.3. Esters of substituted and unsubstituted benzoic acids, for example4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoyl resorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl4-hydroxybenzoate, 2-methyl-4,6-di-tertbutylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methylα-cyano-β-methyl-p-methoxycinnamate, butylα-cyano-β-methyl-p-methoxycinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyidiethanolamine, nickeldibutyidithiocarbamate, nickel salts of the monoalkyl esters, e.g. themethyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonicacid, nickel complexes of ketoximes, e.g. of2-hydroxy4-methylphenylundecylketoxime, nickel complexes of1-phenyll-4-auroyl-5-hydroxypyrazole, with or without additionalligands.

2.6. Sterically hindered amines, for examplebis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(2,2,6,6-tetramethyl-4-piperidyl)succinate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, linear or cydic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethylpiperidyl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidylyl,2,3,4-butanetetracarboxylate,1,1′-(1,2-ethanediylybis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethyl-piperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenyl)-malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cycliccondensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl-1,3,5-triazineand 1,2-bis(3-aminopropylamino)-ethane, the condensate of2-chloro-4,6-di-4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-pipendyl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, amixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensate ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensate of1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine aswell as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.[136504-96-6]); a condensate of 1,6-hexanediamine and2,4,6-trichloro-1,3,5-triazine as well as N,N-dibutylamine and4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [192268-64-7]);N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimide,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-dodecylsuccinimide,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, areaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]decaneand epichlorohydrin,1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene,N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,a diester of 4-methoxymethylenemalonic acid with1,2,2,6,6-pentamethyl-4-hydroxypiperidine,poly[methylpropyl-3-oxy4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane, areaction product of maleic acid anhydride-aolefin copolymer with2,2,6,6-tetramethyl-4-aminopiperidine or1,2,2,6,6-pentamethyl-4-aminopiperidine.

2.7. Oxamides, for example 4,4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxandide,N,N′-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′di-tert-butoxanilide, mixtures of o- andp-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

2.8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyl-oxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4,-(2)-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxyy-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyly1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)1,3,5-triazine,2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazine,2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine,2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy-2-hydroxypropyloxy]phenyl}4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

3. Metal deactivators, for example N,N′-diphenyloxamide,N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl)hydrazine,N,N′-bis(3,5-di-tert-butyl4-hydroxyphenylpropionyl)hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenyihydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)pxalyldihydrazide, N,N′-bis(salicyloylthiopropionyl dihydrazide.

4. Hydroxylamines, for example N,N-dibenzylhydroxylamine,N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine,N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derivedfrom hydrogenated tallow amine.

5. Nitrones, for example N-benzyl-alpha-phenyonitrone,N-ethyl-alpha-methyinitrone, N-octylalpha-heptyinitrone,N-lauryl-alpha-undecylnitrone, N-tetradecyl-alpha-tridecyinitrone,N-hexadecyl-alpha-pentadecylnitrone,N-actadecyl-alpha-heptadecyinitrone,N-hexadecyl-alpha-heptadecyinitrone,N-ocatadecyl-alpha-pentadecylnitrone,N-heptadecyl-alpha-heptadecylnitrone,N-octadecyl-alpha-hexadecylnitrone, nitrone derived fromN,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

6. Thiosynergists, for example dilauryl thiodipropionate or distearylthiodipropionate.

7. Peroxide scavengers, for example esters of β-thiodipropionic acid,for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

8. Polyamide stabilisers, for example copper salts in combination withiodides and/or phosphorus compounds and salts of divalent manganese.

9. Basic co-stabilisers, for example melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal salts andalkaline earth metal salts of higher fatty acids, for example calciumstearate, zinc stearate, magnesium behenate, magnesium stearate, sodiumricinoleate and potassium palmitate, antimony pyrocatecholate or zincpyrocatecholate.

10. Nucleating agents, for example inorganic substances, such as talcum,metal oxides, such as titanium dioxide or magnesium oxide, phosphates,carbonates or sulfates of, preferably, alkaline earth metals; organiccompounds, such as mono- or polycarboxylic acids and the salts thereof,e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodiumsuccinate or sodium benzoate; polymeric compounds, such as ioniccopolymers (ionomers). Especially preferred are1,3:2,4-bis(3′,4′-dimethylbenzylidene)sorbitol,1,3:2,4-di(paramethyidibenzylidene)sorbitol, and1,3:2,4-di(benzylidene)sorbitol.

11. Fillers and reinforcing agents, for example calcium carbonate,silicates, glass fibres, glass bulbs, asbestos, talc, kaolin, mica,barium sulfate, metal oxides and hydroxides, carbon black, graphite,wood flour and flours or fibers of other natural products, syntheticfibers.

12. Other additives, for example plasti cisers, lubricants, emulsifiers,pigments, rheology additives, catalysts, flow-control agents, opticalbrighteners, flameproofing agents, antistatic agents and blowing agents.

13. Benzofuranones and indolinones, for example those disclosed in U.S.Pat. No. 4,325,863; U.S. Pat. No. 4,338,244; U.S. Pat.No. 5,175,312;U.S. Pat. No. 5,216,052; U.S. Pat. No. 5,252,643; DE-A-4316611;DE-A-4316622; DE-A-4316876; EP-A0589839 or EP-A-0591102 or3-[4-(2-acetoxyethoxy)-phenyl]-5,7di-tert-butylbenzofuran-2-one,5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]-benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one,3-(4-acetoxy-3,5-dimethylphenyl)5,7-di-tert-butylbenzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butylbenzofuran-2-one,3-(3,4-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one,3-(2,3-dimethylphenyl-5,7-di-tert-butylbenzofuran-2-one.

In a method of the present invention, a base polyester is modified bymelt mixing the polyester with the masterbatch of the present invention.Condensation or transesterification catalysts may also be added to themelt mixing process in order to enhance the reaction rate of the polyolbranching agent, and if present chain coupling agent, with the basepolyester.

In a specific embodiment the masterbatch composition also includes acondensation or transesterificabon catalyst.

Typical transesterification or condensation catalysts include, but arenot limited to, Lewis acids such as antimony trioxide, titanium oxideand dibutyltin dilaurate.

Other additives which may be incorporated with the masterbatch duringmelt mixing to modify the polyester include monofunctional additives toact as blockers so as to control the degree of chain extension and/orbranching, as described by Edelman et al. in U.S. Pat. No. 4,1611,579,for the production of controlled branched polyesters by a combination ofcondensation/solid state polycondensation. Examples of suitablemonofunctional additives include acids (eg. benzoic acid) or anhydridesor esters thereof (eg. benzoic acid anhydride, aoetic anhydride).Monofunctional alcohols may also be used.

Additives (eg. carbonates) may be incorporated to enhance foaming of themodified polyester where foamed products are required. Gases may also beinjected into the molten polyester during melt mixing in order toachieve physical rather than chemical foaming.

In a method of the present invention a base polyester is modified bymelt mixing it with the masterbatch of the present invention. Meltmixing may conveniently be achieved by continuous extrusion equipmentsuch as twin screw extnuders, single screw extruders, other multiplescrew extruders and Farell mixers. Semi-continuous or batch polymerprocessing equipment may also be used to achieve melt mixing. Suitableequipment includes injection moulders, Banbury mixers and batch mixers.Static mixing equipment may include pipes containing fixed obstaclesarranged in such a way as to favour the subdivision and recombination ofthe flow to thoroughly mix the masterbatch, and any other additives oragents used, with the polyester.

The molecular structure of a modified polyester formed by the method ofthe present invention may exhibit a degree of branching. As discussedabove, it may also be necessary to increase the molecular weight of themodified polyester to effect an increase in the polymers melt strengthand melt viscosity. This can conveniently be achieved in a number ofways, for example the modified polyester may be subjected to a solidstate condensation process, or a chain coupling agent may be used in themodification process itself.

Modified polyesters that exhibit improved melt strength may beadvantageously used in blown film applications where higher meltviscosity, viscoelasticity and strength in the melt allow higher blow upratios, greater biaxial orientation and faster through-puts whilemaintaining bubble stability.

The increased melt strength can be easily detected by an increase of thediameter of the polyester strand at the die of the extruder (i.e. dieswell), compared to unmodified polyester. Further apparatus/parametersfor characterizing the melt strength are: Goettfert Rheotens, uniaxialelongational viscosity and dynamic rheology.

The improved melt rheology of such modified polyester advantageouslyallows the reduction in processing steps and improvement in materialproperties. The improvements in melt rheology can allow the modifiedpolyesters to be processed without prior drying, and facilitate the blowmolding of polyesters. In particular, the improvements in the meltrheology facilitate stretch blow molding, facilitate the foaming ofpolyesters, enhance adhesion of the polyester to polar fillers such asthose used in glass reinforced polyesters, and permit polyesters to bethermoformed with greater ease.

The use of the masterbatch composition according to the invention isbeneficial within several plastic applications, for instance:

-   -   Beverage or cosmetic articles bottles    -   Film packaging for food or non-food    -   Sheets (e.g. thermoformable) for packaging (trays), construction        or automotive applications    -   Injection molded articles    -   Belts or strappings    -   Profiles or pipes    -   Drums    -   Bottle crates    -   Textiles and non-wovens

The benefits caused by the instant masterbatch compositions are forexample based on following effects:

-   -   Higher productivity according to adjusted melt rheology of the        polyester (simpler processing)    -   Reaching technical feasibility of performing extrusion blow        molding or extrusion blowing films with modified polyesters    -   Increasing molecular weight or/and melt strength without        discoloration or gel formation    -   Increasing long-term thermal stability by initially higher        molecular weight    -   Increasing mechanical properties (e.g. better tensile strength,        higher elongation at break, higher burst pressure of bottles)    -   Improved impact properties (e.g. impact strength at ambient and        temperature of −40° C., which is for example important for        achieving better drop test result of frozen food articles in a        tray)    -   Enhanced gas barrier (e.g. O₂, CO₂) by higher molecular weight        and modified polymer chain structure    -   Superior thermal dimensional stability by higher molecular        weight and modified polymer chain structure    -   processing polyester without pre-drying    -   compensating loss of molecular weight (I.V. loss) during melt        processing    -   up-grading lower value PET grades during processing    -   recycling of degraded PET (post consumer or production waste)    -   pultrusion of PET-fibers    -   matching processing properties of C-PET (crystallizable)    -   replacing e.g. polycarbonate by modified polyesters

The masterbatches of the present invention may be preferably used in thefollowing applications. Modification of bottle grade (IV˜0.80) orrecycle PET to produce a polyester suitable for thernoforming.Modification of recycle PET to produce a polyester suitable forreforming into bottles. Modification of bottle or recycle PET to producea polyester suitable for extrusion blow molding. Modification of bottleor recycle PET to produce a polyester suitable for foaming.

Consequently a further aspect of the invention is the use of a polyestermasterbatch composition as described above for the modification ofpolyesters.

The present invention is further described with reference to thefollowing non-limiting examples.

EXAMPLES

Preparation of Masterbatches:

A) Masterbatches Comprising Pentaerythritol or Pyromellitic Dianhydride

Masterbatches were prepared using a Japanese Steel Works (JSW) TEX 30twin screw extruded. The carrier polyester used was PETG (Eastar 6763).Prior to preparing the masterbatches, the PETG was dried in adehumidifier dryer at 75° C. for 2.5 days. The polyol branching agentused was pentaerythritol, and pyromellitic dianhydride was used as acoupling/branching agent. Prior to preparing the masterbatches thepentaerythritol and pyromellitic dianhydride were dried in separatevacuum ovens at 150° C. for 3 days.

The PETG was melt mixed with a metered amount of the pentaerythritol orpyrqmellitic dianhydride and extruded in the form of a strand which wascooled under dry nitrogen then pelletized. The temperature of thebarrels of the extruder were set at 170 (feed section), 180, 180, 180,180, 180, 180, 180, 180, 180° C., with a 10 mm diameter rod die set at180° C. The resulting masterbatches contained 5 weight percent, and 20weight percent of pentaerythritol and pyromellitic dianhydride,respectively. For experimental data see Table 1.

B) Masterbatch Comprising Pentaerythritol and Pyromellitic Dianhydrideand a Catalyst

A masterbatch was prepared using a Japanese Steel Works (JSW) TEX 30twin screw extruded. The carrier polyester used was PETG (Eastar 6763).Prior to preparing the masterbatch, the PETG was dried for 50 hours at85° C. in a nitrogen forced oven. The polyol branching agent used waspentaerythritol, and pyromelliuic dianhydride was used as abranching/chain coupling agent. A transesterification catalyst (antimonytrioxide) was also included in the masterbatch. Prior to preparing themasterbatch, the pentaerythritol, pyromellitic dianhydride and theantimony trioxide were dried in a vaccum over overnight at 120° C. Toassist in the introduction of the agents to the PETG during the meltmixing step, the agents were blended with a small amount of PET powder(BK2180, melt processing temperature of about 270° C.).

The PETG was melt mixed with a metered amount of aforementioned agentsand extruded in the form of a strand which was cooled under dry nitrogenthen pelletized. The temperature of the barrels of the extruder were setat 170 (feed section), 180, 180, 180, 180, 180, 180, 180, 180, 180° C.,with a 10 mm diameter rod die set at 180° C. The resulting masterbatchcontained 2.72 weight percent of pyromellitic dianhydride, 0.33 weightpercent of pentaerythritol and 0.04 weight percent of antimony trioxide.For experimental data see Table 2.

In the following Tables CE#=comparative example, and EX#=example number# TABLE 1 Preparation of the masterbatches EX-1 and EX-2 Melt Melt DropTime Temp Sample PDMA Pentaerythritol PETG Motors Temperature Pressurefrom die Die ID Wt % Wt % Wt % Amps (° C.) (JSW) (kg/cm2) (seconds) (°C.) Comments CE-1 0 0 100 19 232 2 16.7 232 Clear Product EX-1 20 0 8018 — — — — Hazy Product EX-2 0 5 95 18 — — — — Hazy Product

TABLE 2 Preparation of the masterbatch EX-3 Antimony Melt Melt Drop TimeTemp Sample PDMA Pentaerythritol Trioxide BK2180 PETG Motor TemperaturePressure from die Die ID Wt % Wt % wt % Wt % Wt % Amps (° C.) (JSW)(kg/cm2) (seconds) (° C.) Comments CE-2 0 0 0 0 100 19 232 2 16.7 232Clear Product EX-3 2.72 0.33 0.04 6.00 90.91 17 222 0 18.8 213 HazyProductModification of a Base Polyester Using the Masterbatches Prepared inEX-1 to EX-3

A base polyester (BK3180, a bottle grade PET having a melt processingtemperature of about 270° C. and an IV=0.82 dL/g) was modified usingmasterbatches prepared in EX-1 and Ex-2. Prior to modifying the basepolyester, it was dried overnight in a dehumidifier drier at 130° C. ThePETG masterbatches, Ex-1 and Ex-2, were dried for 48 hours at 85° C.under nitrogen.

The base polyester was melt mixed with a metered amount of a blend ofmasterbatches Ex-1 and Ex-2 to afford a concentration of the agents inthe base polyester of 0.25 weight percent pyromellitic dianhydride, withan 8:1 molar ratio of pyromellitic dianhydride to pentaerythritol (i.e.0.0194 weight percent of pentaerythritol). The temperature profile ofthe extruder was: 260° C., 280° C. (by 10), the die used was a 10 mmBrabender strand die. The extrudate exhibited a significant amount ofdie swell, indicating than an appreciable amount of chainbranching/coupling has occurred. For experimental data see Table 3.

A base polyester (Shinpet 5015W, a bottle grade PET having a meltprocessing temperature of about 270° C. and an IV=0.75 dL/g) wasmodified using the masterbatch prepared in Ex-3. Prior to modifying thebase polyester, it was dried overnight at 130° C. under nitrogen. ThePETG masterbatch, EX-3 was dried for 48 hours at 85° C. under nitrogen.

The base polyester was melt mixed with a metered amount of masterbatchEx-3 to afford a concentration of the agents in the base polyester of0.27 weight percent pyromellitic dianhydride, 0.03 weight percentpentaerythritol and 0.004 weight percent of antimony trioxide. Thetemperature profile of the extruder was: 260° C., 280° C. (by 10), thedie used was a 10 mm Brabender strand die. The extrudate exhibited asignificant amount of die swell, indicating that an appreciable amountof chain branch/coupling has occurred. For example experimental data seeTable 4. TABLE 3 Modification of base polyester using masterbatches Ex-1and Ex-2 Melt Melt Drop Time Temp Sample EX-1 EX-2 BK3180 ModifiersMotor Temperature Pressure from die Die ID Wt % Wt % Wt % wt % Amps (°C.) (JSW) (kg/cm2) (seconds) (° C.) Comments CE-3 0 0 100 PDMA = 0 10280 2 4 282 Clear Penta = 0 Product EX-4 1.25 0.39 98.36 PDMA = 0.25 22— — — — Clear Penta = 0.0194 Product, showing die swell

TABLE 4 Modification of base polyester using masterbatch Ex-3 ShinpetMelt Melt Drop Time Temp Sample EX-3 5015W Modifiers Motor TemperaturePressure from die Die ID Wt % Wt % wt % Amps (° C.) (JSW) (kg/cm2)(seconds) (° C.) Comments CE-4 0 100 PDMA = 0 10 280 2 4 282 Clear Penta= 0 Product EX-5 10 90 PDMA = 0.27 12 284 0 8 284 Clear Penta = 0.03Product, showing die swellAnalysis of the Masterbatches Prepared in Ex-1 and Ex-2 by NMRSpectroscopySample Preparation:

A sample of PETG (30 mg, Eastar 6763), as a control, was dissolved inCDCl₃ (0.5 mL), after dissolution the mixture was transferred to an NMRtube and an excess of trichloroacetyl isocyanate (10 μL, 6.3 mg, 3.36mmol) was added. The ¹H NMR spectrum was recorded at room temperature ona Bruker DRX 500 operating at 500 MHz ¹H NMR (CDCl₃, ppm, δ): 8.05 (M,99H, ArH), 8.50 (m, 0.30H, NH Alcohol), 8.65 (s. 0.08H, NH Alcohol),10.36 (s, 1H, NH Acid).

A sample of masterbatch EX-1 (pyromellitic dianhydride) (30 mg) wsdissolved in CDCl₃ (0.5 mL), after dissolution the mixture was filteredand transferred to an NMR tube and an excess of trichloroacetylisocyanate (10 μL, 6.3 mg, 3.36 mmol) was added. The ¹H NMR spectrum wasrecorded at room temperature on a Bruker DRX 500 operating at 500 MHz.¹H NMR (CDCl₃, ppm, δ): 8.05 (m, 71H, ArH), 8.50 (m, 0.10H, NH Alcohol),10.36 (s, 1H, NH Acid).

A sample of masterbatch EX-2 (pentaerythritol) (30 mg) was dissolved inCDCl₃ (0.5 mL), after dissolution the mixture was transferred to an NMRtube and an excess of trichloroacetyl isocyanate (10 μL, 6.3 mg, 3.36mmol) was added. The ¹H NMR spectrum was recorded at room temperature ona Bruker DRX 500 operating a 500 MHz. ¹H NMR (CDCl₃, ppm, δ): 8.05 (m,85H, ArH), 8.55 (m, 0.30H, NH Alcohol), 10.36 (s, 1H, NH Acid).

Results:

Addition of trichloroacetyl isocyanate (TAI) to a chloroform solution ofPETG gives rise to a number of additional peaks in the ¹H NMR spectrumwhich occur at δ 10.36, 8.65 and 8.50 ppm. The signal at δ10.36 ppm hasbeen assigned to the adduct resulting from the reaction between TAI andthe acid end groups of PETG. The other two signals at δ8.65.

C) Preparation of Masterbatches Comprising Polyols or PMDA

The following examples show that both low melting (trimethylolpropane mp60° C.) and high melting polyols (pentaerythritol mp 255° C.) may usedto form PETG masterbatches when a low processing temperature (170° C.)is used.

Masterbatches were prepared using a Brabender single screw extruder (19mm diameter screw with compression ratio˜3:1 and fdted with slottedmixing head) with, L/D=25:1, three heated zones and a 6 mm rod die. Thelow temperature profile had the three heated zones at 160° C., 170° C.,170° C. and die at 170° C. The high temperature profile had the threeheated zones at 260° C., 270° C., 270° C. and die at 270° C. A nitrogenblanket was maintained over the feed throat.

Moisture levels were determined with a Arizona Instruments Computrac3000 Moisture Analyzer on samples heated at 80° C.

The carrier polyester used was PETG (Eastar 6763). Prior to preparingthe masterbatches, the PETG pellets were dried in a vacuum oven at 75°C. for 48 hrs (moisture level after drying was 55 ppm H₂O, melt flowindex at 270° C. was 18.35 g/10 min). PETG powder was dried in vaccumoven at 75° C. for 3 hrs (moisture level after drying was 215 ppm H₂O,melt flow index at 200C was 1.13 g/10 min). Prior to preparing themasterbatches the PMDA and pentaerythritol were dried in a vacuum ovenat 100° C. for 15 hours. Trimethylolpropane was used as received.

The PETG was mixed with a weighed amount of the polyol or PMDA andextruded in the form of a strand, which was cooled under dry nitrogenthen pelletized. The temperature of the barrel of the extruder was setat as indicated in the Table 5-10. For experimental data see Tables5-10. TABLE 5 Formation of masterbatch at 170° C. with pentaeryithritol(Penta) pressure throughput Drop MFI Additive Additive Example * C. rpmtorq psi g/kg Time g/10 min % Used control 170 10 1315 93 369.6 147.561.3 0 none EX6 170 10 1213 91 299.9 181.02 1.2 0.3 Penta EX7 170 10 113092 314 209.85 1.35 1 Penta

TABLE 6 Attempted formation of masterbatch at 270° C. withpentaeryithritol (Penta) pressure throughput Drop MFI Additive AdditiveExample * C. rpm torq psi g/kg Time g/10 min % Used control 270 10 0 0246 14.41 3.63 0 none CE 270 10 0 0 302.8 9.53 24.52 0.3 Penta CE 270 100 0 304.8 4.16 43.89 1 Penta

TABLE 7 Formation of masterbatch at 170° C. with trimethylolpropane(TMP) pressure throughput Drop MFI Additive Additive Example * C. rpmtorq psi g/kg Time g/10 min % Used control 170 10 1315 93 369.6 147.561.3 0 none EX8 170 10 1618 63 431 148.25 1.88 0.3 TMP EX9 170 10 1029 43287 181.25 1.77 1 TMP

TABLE 8 Attempted formation of masterbatch at 270° C. withtrimethylolpropane (TMP) pressure throughput Drop MFI Additive AdditiveExample * C. rpm torq psi g/kg Time g/10 min % Used control 270 10 0 0248 14.41 3.63 0 none CE 270 30 0 0 147.2 0.2 67.2 1 TMP

TABLE 9 Formation of masterbatch at 170° C. with PMDA pressurethroughput Drop MFI Additive Additive Example * C. Rpm Torq psi g/kgTime g/10 min % Used control 170 10 1315 93 369.6 147.56 1.3 0 none EX10170 12 1369 78 389.4 159.37 1.22 0.3 PMDA EX11 170 12 1412 83 361.7 1711.27 1 PMDA EX12 170 15 1576 94 395.1 173.11 1.65 10 PMDA

TABLE 10 Attempted formation of masterbatch at 270° C. with PMDAPressure Throughput Drop MFI Additive Additive Example * C. Rpm Torq psig/kg Time g/10 min % Used CE 270 10 0 0 248 14.41 3.63 0 none CE 270 100 0 255 15.72 2.76 0.30% PMDA CE 270 10 0 3 191.3 19.03 2.21 0.30% PMDACE 270 10 0 6 155.9 22.81 1.81 1.00% PMDAD) Preparation of Masterbatches Comprising Different Carrier Polyesterand Additives.

Intrinsic Viscosity (I.V.):

1 g polymer is dissolved in 100 g of a mixture ofphenolidi-chlorobenzene (1/1). The viscosity of this solution ismeasured at 30° C. in an Ubelode-viscosimeter and extrapolated to givethe intrinsic viscosity.

Color

Color (b value of the Yellowness Index) is measured according to ASTMD1925 using a Hunter Lab Scan instrument

Melt Flow Rate (MFR):

MFR is determined with a Goettfert MP-P according to ISO 1133 at 260° C.with 2.16 kg weight after pre-drying the polyester.

Materials:

All carrier polyesters are dried prior to use (>12 h at 60° C. invacuum)

Carrier Polyester A:

Polyester with following composition:

81.8 mol % p-terephthalic acid

18.2 mol % isophthalic acid

96.9% ethylene glycol

3.1% diethylene glycol

Commercial product of NanYa Plastics America Inc.

The polyester has a melt viscosity of 1315 Pa sec at a shear rate of 100sec⁻¹ at 190° C., measured within Goettfert capillary rheometer“Rheograph 2001”; 10 mm capillary length, 1 mm capillary diameter.

Carrier Polyester B:

Polyester with following composition:

70.1 mol % p-terephthalic acid

29.9 mol % isophthalic acid

92.9% ethylene glycol

7.1% diethylene glycol

Commercial Product of NanYa Plastics America Inc.

The polyester shows a melt viscosity of 1035 Pa sec at a shear rate of100 sec⁻¹ at 200° C., measured within Goettfert capillary rheometer“Rhograph 2001”; 10 mm capillary length, 1 mm capillary diameter.

Carrier Polyester C:

Poly-ε-caprolactone ex Fluka

The polyester shows a melt viscosity of 858 Pa sec at a shear rate100/sec at 160° C. (measured within Goettfert capillary rheometer“Rheograph 2001”; 10 mm capillary length, 1 mm capillary diameter)

Chain Coupling Agents:

PMDA 1 ex Beyo (China) (powder) (melt temperature: 284° C.)

PMDA 2 ex Beyo (China) (coarse) (melt temperature: 287° C.)

Allinco® ex DSM (=dodecahydro-1,1′-carbonyl-bis azepin-2-one, CAS RN19494-73-6)

Branching Agent:

Pentaerythrol ex Perstorp (Finland) (melt temperature: 262° C.) (=Penta)

Further Additives:

Irgamod 195 a phosphonate, commercial product of Ciba SpecialtyChemicals,

Irganox 1222 a phosphonate, commercial product of Ciba SpecialtyChemicals,

IRGAFOS 12 a phosphite, commercial product of Ciba Specialty Chemicals,

IRGAFOS 168 a phosphite, commercial product of Ciba Specialty Chemicals

IRGANOX HP136 a lactone, commercial product of Ciba Specialty Chemicals

Compound 101: synthesized by standard procedure

Compound 102: Di-isooctylphosphinic acid, purchased ex Fluka

Base Polyester (To be Modified by Masterbatches):

All base polyesters are dried prior to use (>12 h at 80° C. in vacuum)

PET D: Polyclear T94 supplied by KoSa Gersthofen

PET E: Polyclear RT48 supplied by KoSa Gersthofen

PET F: Polydear RT21 supplied by KoSa Gersthofen

PET G1: ICI LaserPlus supplied by ICI

PBT X: Crastin SK605 NCO10 supplied by DuPont

Examples MB1 to MB23

Producing masterbatch according to procedure A

General procedure A:

In a twin screw extruder (ZSK 25 from Werner & Pfleiderer) with screwsrotating in the same direction, the below mentioned formulations areextruded at a temperature of T_(max)=180° C. (heating zone 1-6), athroughput of 5 kg/h, 100 rev/min and pelletized in a water bath.

The general procedure A is applied to following compositions: PolyesterChain coupling Branching Ex. No. Carrier agent agent Additive Comp A100% A  — — — Comp B 95% A — — 5% Irgamod 195 MB1 95% A — 5% Penta — MB290% A 10% PMDA 1 — — MB3 89% A 10% PMDA 1 1% Penta — MB4 88% A 10% PMDA1 2% Penta — MB5 88% A 10% PMDA 1 1% Penta 1% Irgamod 195 MB6 89% B 10%PMDA 1 1% Penta — MB7 88% B 10% PMDA 1 1% Penta 1% Irgamod 195 MB8 88% B10% PMDA 1 — 2% Irgamod 195 MB9 75% B 25% PMDA 1 — — MB10 72.5% B   25%PMDA 1 2.5% Penta   — MB11 70% B 25% PMDA 1 2.5% Penta   2.5% Irgamod195 MB12 70% B 25% PMDA 1 — 5% Irgamod 195 MB13 89% C 10% PMDA 1 1%Penta — MB14 88% A 10% PMDA 1 1% Penta 1% Irgafos 168 MB15 88% A 10%PMDA 1 1% Penta 1% Irgafos 12 MB16 90% A 10% Allinco — — MB17 89% A 10%Allinco — 1% Irgamod 195 MB18 89% A 10% Allinco 1% Penta — MB19 88% A10% Allinco 1% Penta 1% Irgamod 195 MB20 89% A 10% PMDA 1 1% Penta 1%Irgafos HP136 MB21 89% A 10% PMDA 1 1% Penta 1% compound 101 MB22 89% A10% PMDA 1 1% Penta 1% compound 102 MB23 89.4% A   10% PMDA 1 0.5%Penta   0.1% Sb₂O₃

Examples MB24 to MB27

Producing masterbatch according to procedure B

General procedure B:

In a Buss co-kneader (MDK 140), with a separate transversal screw forextrusion into the die, the below mentioned formulations are extruded atbody temperature of 210° C., kneader axe and die temperature of both180° C., a throughput of 400 kg/h, 140 rev/min (kneader axe) andpelletized in a water bath.

The general procedure B is applied to following compositions: PolyesterChain coupling Branching Ex. No. Carrier agent agent Additive Comp C100% B  — — — MB24 89% B 10% PMDA 1 1% Penta — MB25 88% B 10% PMDA 1 1%Penta 1% Irgamod 195 MB26 88% B 10% PMDA 1 — 2% Irgamod 195 MB27 76% B20% PMDA 2 2% Penta 2% Irgamod 195E) Modification of Base Polymer Using the Masterbatches:General Procedure

In a twin screw extruder (ZSK 25 from Werner & Pfleiderer) with screwsrotating in the same direction, the below mentioned formulations wereextruded at a temperature of T_(max)=280° C. (heatng zone 1-6), athroughput of 6 kg/h and 100 rev/min and pelletized in a water bath.

The general procedure is applied to the following comparative examples.MFR Base g/10 I.V. Color Ex. No. Polyester Additives min dl/g B*-valueComp D 100% E — 62 0.55 0.92 Comp E 100% E 0.2% PMDA 1 25 0.66 9.2 0.02%Penta 0.02% Irgamod 195 Comp F 100% F — 18 0.57 — Comp G 100% G1 — 140.75 — Comp H 100% D — 16 0.76 —

The general procedure is applied to the following examples C1-C25.Equivalent to MFR I.V. Color Ex. No. Polyester Masterbatch additivecomposition g/10 min dl/g B*-value Ex C1 100% E 2% MB15 0.2% PMDA 1 210.69 −1.3 0.02% Penta 0.02% Irgamod 195

The performance of the masterbatch MB15 is much better (with regard todecrease of MFR, increase of I.V. and color) compared to the addition ofthe active ingredients directly (as tested in the comparative exampleComp E). Base MFR I.V. Ex. No. Polyester Masterbatch G/10 min dl/g Ex C2100% D 1% MB2 6.3 0.84 Ex C3 100% D 3% MB2 + 2.1 0.91 0.6% MB1 Ex C4100% D 1% MB3 8.7 0.86 Ex C5 100% D 1% MB3 + 4.3 0.94 0.5% Comp B Ex C6100% D 1% MB4 9.4 0.82 Ex C7 100% D 1% MB5 8.3 0.86 Ex C8 100% E 3% MB611 0.74 Ex C9 100% E 3% MB7 14 0.72 Ex C10 100% E 3% MB8 9.0 0.75 Ex C11100% G1 1% MB9 7.4 0.80 Ex C12 100% G1 1% MB10 9.0 0.78 Ex C13 100% G11% MB11 8.6 0.81 Ex C14 100% G1 1% MB12 11 0.80 Ex C15 100% E 3% MB13 100.73 Ex C16 100% E 3% MB14 11 0.75 Ex C17 100% E 3% MB15 9.8 0.75 Ex C18100% D 3% MB16 15 0.76 Ex C19 100% D 3% MB17 14 0.81 Ex C20 100% D 3%MB18 14 0.82 Ex C21 100% D 3% MB19 13 0.83 Ex C22 100% E 2% MB20 14 0.70Ex C23 100% E 2% MB21 15 0.71 Ex C24 100% E 2% MB22 15 0.72 Ex C25 100%E 2% MB23 16 0.70F) Producing Extrusion-Blown Films

General procedure:

In a twin screw extruder (Haake TW100, counter-rotating conical screws),the below mentioned formulations are extruded at a temperature ofT_(max)=280° C., a throughput of 1.8 kg/h and 60 rev/min into a filmblowing die.

The general procedure is applied to comparative examples M and N and tothe examples D1 and D2 according to the invention. Base Film Ex. No.Polyester Additives thickness Remarks Comp M 100% D — *** Comp N 100% D0.3% PMDA 1 25.3 μm Yellow film 0.03% Penta Many gels Ex D1 100% D 3%MB3 17.5 μm No discoloration No gels Ex D2 100% D 3% MB5 10.9 μm Nodiscoloration No gels*** extrusion blowing a film was not feasible due to too low meltstrength

1. A polyester masterbatch composition comprising a branching and/or achain coupling agent dispersed within a polymeric matrix of polyester,wherein the polyester has a melt processing temperature of 250° C. orless.
 2. A polyester masterbatch composition according to claim 1wherein the agent is a chain branching agent.
 3. A polyester masterbatchcomposition according to claim 2 wherein the chain branching agent is apolyol.
 4. A polyester masterbatch composition according to claim 1wherein the agent is a chain coupling agent.
 5. A polyester masterbatchcomposition according to claim 4 wherein the chain coupling agent is adianhydride.
 6. A polyester masterbatch composition according to claim 1wherein the agents are a chain branching agent and a chain couplingagent.
 7. A polyester masterbatch composition according to claim 6wherein the chain branching agent is a polyol and the chain couplingagent is a dianhydride.
 8. A polyester masterbatch composition accordingto claim 1 wherein the polyester's melt viscosity and/or the polyester'sintrinsic viscosity is reduced or increased by no more than 30% when itis melt mixed with the branching and/or chain coupling agent.
 9. Apolyester masterbatch composition according to claim 1 wherein thebranching and/or chain coupling agent has a melt temperature which is atleast 10° C. higher than the melt processing temperature of thepolyester.
 10. A polyester masterbatch composition according to claim 1wherein the polyester suitable or use in the masterbatch has a meltprocessing temperature ranging from 150° C. to 250° C.
 11. A polyestermasterbatch composition according to claim 1 wherein the polyestersuitable for use in the masterbatch has a crystallinity of less than15%.
 12. A polyester masterbatch composition according to claim 1wherein the polyester suitable for use in the masterbatch is glycolmodified poly(ethylene terephthalate) (PETG), poly-ε-caprolactone, or acopolyester containing greater than about 15% isophthalic units.
 13. Apolyester masterbatch composition according to claim 1 wherein thebranching agent is a polyol, which is present in an amount of from 0.3to 30 weight percent based on the weight of the polyester masterbatchpolymer.
 14. A polyester masterbatch composition according to claim 1wherein the chain coupling agent is present in an amount of from 1 to 60weight percent based on the weight of the polyester masterbatch polymer.15. A polyester masterbatch composition according to claim 1, whichadditionally comprises a phosphite, a phospinate or a phosphonatecompound.
 16. A polyester masterbatch composition according to claim 15wherein the phosphonate is of formula III, IV, V, VI or VII

wherein the R₁₀₁ are each independently of one another hydrogen orM^(r+)/r.
 17. A polyester masterbatch composition according to claim 1,which also includes a condensation or transesterification catalyst. 18.A method of preparing a polyester masterbatch comprising melt mixing apolyester with a branching and/or chain coupling agent such that thebranching and/or chain coupling agent is dispersed within the polymericmatrix of the polyester, wherein the polyester has a melt processingtemperature of 250° C. or less.
 19. A method for modifying a polyestercomprising melt mixing the polyester at a temperature above 250° C.together with a polyester masterbatch according to claim
 1. 20. Use of apolyester masterbatch composition according to claim 1 for themodification of polyesters.